This is a rare litigation era model. It has a beautiful inlay on the neck. I have owned since 1978. It sounds fantastic. I will post a picture shortly. This is a quote about the F309S that I found on the net...
I bought an upgraded 1972 version of F-390S with the large mother of pearl inlays on the fingerboard and the gold tuning machine/pegs and extra ivory. I bought it out of a collection of about 350 guitars that a friend had purchased to get to a couple of 1934 Gibson Accoustics. I had Ron Pace of Pace Guitar in Houston re-fret and straighten the neck and install a top of the line internal pick-up. In all I spent an extra $650 more on this guitar. I love it. I play it every day and the sound isn't just good; it is spectacular! I am also a pianist and violinist. I choose my instruments based on the sound and the playability. I have been offered over $2,500 for this guitar from a couple of pros but I won't sell it. The sound is so incredible and Ron Pace did such a good job for me that I will probably pass it to my kids someday when I'm gone instead of selling it. It isn't the dollars; it is the sound that counts. So, count yourself lucky if you have one. The sound is probably great now and it will only get better with age.